Phase Separated Fibrous Structures: Mechanism Study and Applications

Abstract

Phase separation is one of the most important technologies to fabricate ultrafine fibers. Different from electrospinning, phase separation can produce fibers arranged in three dimension and thus has unique advantages, such as mimicking the fibrous structure in extracellular matrix more closely. However, to precisely control the architectures of phase separated scaffolds is challenging. This chapter introduces the current understanding about the mechanisms of phase separation and summarizes the factors, which can control the morphologies of resultant scaffolds. Methods to produce fibrous phase separated scaffolds are discussed in this chapter. Applications and limitations are also analyzed.

Gelatin/EGDE Ultrafine Composite Fibers Reinforced with 3D Spacer Fabric as Bicomponent Scaffolds for Tissue Engineering

“…Once the polymer concentrations increased to 0.5 and 1 wt %, the fibrous structure was replaced by fused films, resulting in a sponge morphology. A similar trend was observed in previous studies for CA cross-linked scaffolds. , The solutions with low polymer concentrations initiated the aggregation of polymers under the phase separation conditions based on the “solvent crystal templating theory” where the rapid quench brought the solution state under a binodal curve of the phase diagram (see Figure S1, Supporting Information) with two phases coexisting . The large amount of solvent kept forming crystals in the solvent-rich phase.…”

“…13,33 The solutions with low polymer concentrations initiated the aggregation of polymers under the phase separation conditions based on the "solvent crystal templating theory" 34 where the rapid quench brought the solution state under a binodal curve of the phase diagram (see Figure S1, Supporting Information) with two phases coexisting. 35 The large amount of solvent kept forming crystals in the solvent-rich phase. On the contrary, a very low polymer concentration could not initiate nucleation in the polymer-rich phase and experienced the continuous push from the growing solvent crystals.…”

Sustained Local Delivery of Diclofenac from Three-Dimensional Ultrafine Fibrous Protein Scaffolds with Ultrahigh Drug Loading Capacity

“…Since the polymer concentration was ultra-low, the amount of polymer was not sufficient to form connected chips, and hence, fine fibers were produced. The solvent crystals were large enough to segregate these fibers and produce large pores during the lyophilization process [21].…”